XVI PEOCEEDINGS OF THE 



tions on the conjugation of Paramecium aurelia*. He is led, how- 

 ever, to doubt the validity of the sexual interpretation of the conju- 

 gation. He found that in certain cases in Paratnecium aurelia and 

 in P. colpoda the so-called spermatic capsule into which the nu- 

 cleolus had become converted had entirely disappeared, without any 

 evident change in the nucleus ; and he concludes that fecundation 

 of the bodies regarded by Balbiani as eggs cannot be here enter- 

 tained. Indeed he will not allow that we have evidence entitling 

 us to regard the appearance of filaments io the interior of the nu- 

 cleolus as affording any indication of true spermatozoa. He offers 

 no explanation of this appearance ; but he calls attention to the fact 

 that both Balbiani and Stein noticed that in transverse division of 

 the Infusoria (a phenomenon with which conjugation can have 

 nothing to do) the nucleolus frequently enlarges and acquires a lon- 

 gitudinal striation, like that of the nucleolus in the supposed pro- 

 duction of spermatozoa during conjugation, Balbiani, it is true, main- 

 tains that this striation during cleavage is only superficial ; but it never- 

 theless affords an argument against assigning any more important 

 significance to the very similar appearance in the case of conjugation. 



On the whole, it would appear that the spermatozoal nature of 

 the striae visible in the nucleolus of the conjugating individuals (even 

 admitting that these striae represent isolatable filaments) has not by 

 any means been proved ; while the phenomenon of conjugation in 

 the Infusoria would seem to correspond rather with the conjugation 

 so well known in many lower organisms, where it takes place with- 

 out being in any way connected with the formation of true sexual 

 products. 



In the same memoir the results of observations on some other 

 points in the structure and economy of the Infusoria have also been 

 given by Biitschli. He records the occurrence of minute crystal- 

 like laminae in the interior of a marine Infusorium (Stroynbidium 

 sulcatum), rendered remarkable by a conspicuous girdle of tricho- 

 cysts which surround its body. The crystal-like corpuscles seem 

 to be of the nature of starch ; for on the application of iodine they 

 assume a beautiful violet colour. It does not appear from Biitschli's 

 account of these bodies that they have not been introduced from 

 without ; and the chief interest of the obser\'ation seems to be in the 

 discovery of an amylaceous body assuming a crystalline form. He 

 had previously met with similar bodies in a parasitic Infusorium 

 (^Nyctotherus ovalis) as well as in a Gregarina (G. blattariun). 



* O. Butscbli, " Einiges iiber Infiisorien,' Archiv f. mikroskop. Anat. 1873. 



